textproduct: Albany

WHAT HAS CHANGED

A Flood Watch was issued from 8 am Tue to 8 pm Wed for Herkimer and Hamilton Counties for recent wet soils, the potential for minor flooding due to 1-2" of rainfall and some snow melt. Thunderstorm probabilities were expanded late tonight through Tuesday. Temps were lowered from the Capital Region northward Wed for the frontal passage, though the placement of the front is uncertain how far south it will progress during the day.

KEY MESSAGES

1) An excellent RH recovery tonight with some isolated-scattered showers will ease fire weather concerns for western MA.

2) Multiple rounds of showers and widely scattered t-storms are expected late tonight through Wed afternoon. Highest confidence for 1-2 inches of rainfall is over the SW Adirondacks/western Mohawk Valley, where a Flood Watch was issued Tue morning through Wed.

3). Another storm system is expected to bring additional precipitation to the region Thu into next weekend. Outside of the northern mountains (wintry mix), precipitation looks to fall mainly as rain.

DISCUSSION

KEY MESSAGE 1...A warm afternoon with weak ridging aloft has allowed temps to climb 15-20 degrees above normal with partly sunny skies. Highs are in the 50s over the mtns and 60s to lower 70s in the valleys and over the hills. The RH values have lowered into the 25-40% range due to deeper mixing with the south/southwest boundary layer winds. An SPS continues for Elevated Fire Wx Concerns based on input from MA State Partners and WFO BOX. The SPS runs until 6 pm. RH values will begin to climb after that with thickening and lowering clouds ahead of a front lifting northward as warm front towards northern NY and northern New England. Fire Wx concerns diminish for several days ahead with a wet and unsettled stretch.

KEY MESSAGE 2... The mid and upper level flow becomes zonal over the Great Lakes Region into the Northeast. The 850 hPa low-level jet increases with an influx of Gulf moisture ahead of a short-wave and sfc cyclone moving along the frontal boundary north of I-90. The PWATs surge above normal with showers increasing initially west to northwest of the Capital Region around midnight or shortly thereafter, but then expanding across the rest of the region with the isentropic lift with the warm front. The rain continues through the morning, as some thunderstorms are possible with MUCAPEs in the 100-250 J/kg range especially from Albany north and west. We placed slight chances of thunderstorms in the mid to late morning west, and then expanded eastward during the day.

The initial surge of rainfall in the quarter to three quarters of an inch range should not be a threat for Herkimer and Hamilton Counties. Another stronger wave moves along the front Tue pm and night. PWATs rise 1-1.25+" which are 2-3+ STDEVs above normal. The low-level southwest flow increases off the southwest Adirondacks which may enhance rainfall totals a bit. The front starts to push southward across the region Tue night. Max temps on Tue will be in the 60s to lower 70s from the Mohawk Valley, Capital Region, Berkshires/southern VT southward with 50s and even a few upper 40s to north.

In the warm sector ahead of the front, widely scattered to scattered strong t-storms may occur with MUCAPE instability values in the 500-1000 J/kg range, steep mid level lapse rates around 7C/km on some of the CAMS with deep shear 45-50 KT. The question will be if any parcels become surface based for a severe threat. SPC continues a Day 2 Outlook with a Marginal Risk for severe thunderstorms from Albany west/southwest. An isolated severe or two may be possible with large hail or wind damage, if enough heating occurs. The warm sector maybe cluttered with clouds. SPC does have 2% probs with the low-level and deep shear with the boundary nearby the Mohawk Valley.

The additional rainfall may elevate creek/river flows in the western Mohawk Valley and west/southwest Adirondacks. The latest NBM guidance indicates 40-50% probabilities >1" of rainfall for Herkimer and western Hamilton Counties for the 24-hr period ending 12Z/Wed. The latest NERFC forecasts indicate minor flooding forecast for Hinckley Reservoir and Kast Bridge on the West Canada Creek. We collaborated with WFO BUF and BGM on a Flood Watch through Wed pm. The frontal position by 12Z/Wed is variable on the latest short-range and ensemble guidance. It could be near the Mohawk Valley and Capital Region. We blended the NBM/MAVMOS and lowered temps 5-10 degrees below the 13Z NBM north of the mid Hudson Valley. Daytime highs in the 40s and 50s from the Capital Region, northern Catskills, northern Berkshires northward and 60s south and east. Some additional showers persist into the late afternoon with a few thunderstorms near the I84 corridor.

Temps fall Wed night into the 30s with some upper 20s over the Adirondack Park. Some lower 40s are possible in the mid Hudson Valley and northwest CT with some light showers persisting on the backside of the cold front moving into PA and NJ.

KEY MESSAGE 3...The latest NBM/WPC guidance continues to support widespread pcpn returning to the forecast area Thu-Thu night. PoPs increase into the 50-80% range on Thu, as the isentropic lift increases ahead of the old front lifting back northward as a warm front. The WPC guidance supports some snow or a brief period of freezing rain along the eastern spine of the southern Dacks and the southern Greens, especially Thu night. There is a cold damming signature along the northern mtns, which may support the brief icy mix. This would be for the northern mtns. An SPS or an winter wx advisory may be needed, if the freezing rain threat increases, though our confidence remains low. Temps will be rising Thu night through the 30s and 40s. Milder weather returns for Friday with highs in the 60s and 70s with the greatest chances for showers and isolated thunderstorms over the northern zones. Another low pressure system moving W/NW of upstate NY over the holiday weekend could bring more showers ahead of its cold front, though it could be late Saturday or on Sunday.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Flying conditions continue to be VFR across the region for this evening with bkn-ovc mid level clouds around 8-10 kft. Through at least midnight, it will remain dry at all TAF sites with VFR conditions and just some mid level clouds. Southwest winds will be 5-10 kts. Although a few higher gusts have been occurring this evening at KPOU, winds should diminish overnight as nocturnal effects take over.

Some light rain will spread towards the area for the late night hours and into the morning on Tuesday. This will mainly impact KGFL, KALB and KPSF, with a period of MVFR conditions for both visibility and ceilings. KPOU will be on the edge, so will include a TEMPO there, but precip looks more spotty for this site. Southerly winds will be around 5 kts for the late night hours and into Tuesday morning as the batch of light rain moves across the area with visibility in the 3-5SM range and ceilings around 2 kft. Won't include any IFR at this time and while it can't be totally ruled out, it looks like it would be very brief.

Behind the steady rain, moisture will remain in place over the region. This should keep MVFR cigs at KGFL, but the other sites may return to VFR by the afternoon hours, although bkn cigs will remain in place around 4 kft. Some additional passing showers (and perhaps even a thunderstorm) is possible for late in the day, but this activity looks scattered and there may be a better chance after 00z Wednesday. South to southwest winds will increase to 5 to 10 kts for the late morning and afternoon hours and some higher gusts can't be ruled out, mainly for KALB and KPSF.

Outlook...

Tuesday Night: High Operational Impact. Definite SHRA...TSRA. Wednesday: Moderate Operational Impact. Breezy. Likely SHRA. Wednesday Night: Moderate Operational Impact. Chance of SHRA. Thursday: Moderate Operational Impact. Likely SHRA. Thursday Night: Moderate Operational Impact. Chance of RA. Friday: Moderate Operational Impact. Chance of RA...TSRA. Friday Night: Moderate Operational Impact. Chance of RA. Saturday: Moderate Operational Impact. Chance of RA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Flood Watch from Tuesday morning through Wednesday evening for NYZ032-033-038. MA...None. VT...None.